ROCHESTER, NY — Michigan hockey coach Red Berenson knew that a 4-0 lead over the Rochester Institute of Technology was too good to be true.

It was as if the 10th-ranked Wolverines were playing a videogame on the easiest setting. Junior forward Phil Di Giuseppe’s slick deke had quickly put them on the board in the first period. Then senior forward Derek DeBlois doubled the lead, and Di Giuseppe added another.

It was 3-0 before the game was 10 minutes old, and sophomore forward Boo Nieves had followed by capping off the first 20 minutes with a wrist shot that found twine.

But Michigan (2-0) was playing in Rochester, in front of a sold-out Blue Cross Arena packed with more than 10,000 roaring fans. It was homecoming, and orange-clad alumni had made the trip back to scenic upstate New York for what was deemed the biggest home game in history. The Wolverines were up 4-0, but Berenson knew the Tigers (0-2) would claw back.

Did they ever fight back, ripping a hole in Michigan’s defense and drawing even at four in the second period before the Wolverines pulled away for a 7-4 victory that was closer than the score indicated.

“The puck went in too easy for us, and obviously you knew (RIT) was going to push back,” Berenson said. “We weren’t playing as hard, and as smart and as defensive as we should have. … We were on our heels, definitely.”

He was right. The Wolverines’ second period was nothing short of disastrous.

The fans stirred when forward Mike Colavecchia went end-to-end and scored on the power play, finishing the rush with an Ovechkin-esque jump into the boards. Forward Ben Lynch’s goal cut Michigan’s lead to two, and a scrum nearly boiled over into a brawl as parties from both sides were given offsetting minor penalties. When Matt Garbowsky made it 4-3, the sellout crowd went berserk, and the building began to shake when forward Nolan Descoteaux tied the game five minutes later.

RIT fired 17 shots in the second period alone.

Berenson thought the Wolverines had let up after taking such a big lead so early in the game. But he didn’t enjoy the first period, either, which saw the Tigers out-shoot Michigan 16-11.

“I didn’t like the way we were playing even though we scored,” he said.

Were it not for a fluky goal by freshman forward Evan Allen, the Tigers might have pulled off the upset. As the public-address announcer welcomed the last minute of play in the second period, Allen flung a puck at the net from a horrible angle that somehow squeaked by netminder Jordan Ruby. Michigan had surrendered four consecutive goals in the period before Allen’s tally, but somehow escaped with a 5-4 lead at the intermission.

Freshman forward Tyler Motte and sophomore forward Andrew Copp tallied goals late in the third period to seal the Wolverines’ win — one that was much, much closer than the fans expected. The Tigers were playing so poorly in the first period that when the RIT mascot stepped onto the ice during the intermission, its desperate attempts to pump up the crowd were met with a paltry groan.

It wasn’t the first time RIT surprised the Wolverines. In Michigan’s 2012 regular-season opener, the Tigers were victorious at Yost Ice Arena despite trailing by three goals late in the game.

But on Saturday, Michigan’s letdown didn’t lead to an upset.

“It was a good test for our team,” Berenson said. “That’s why you have these games on our schedule.”